Short-cycling in heat pump example

[mwetter]

@FWuellhorst
In the model Fluid.HeatPumps.ModularReversible.Examples.AirToWater2D_OneRoomRadiator the heat pump short-cycles during part of the simulation. It switches on and off in a 1 minute interval during cooling mode.
It looks like the controller needs to be changed to avoid such operation.
This is with the model from #1628 but I suggest to handle this in a new PR so that we can merge #1628 once it passes the CI tests.

[FWuellhorst]

@mwetter :
The underlying issue is that QCoo_flow_nominal is set to a value which oversizes the heat pump during cooling operation:

Warning: The following was detected at time: 0
  In AirToWater2D_OneRoomRadiator.heaPum: Scaling factors for heating and cooling
    operation differ by -25.8333 %. The simulated nominal heating and cooling
    capacities may not be realistic for a single device
  Failed condition: abs(heaPum.scaFacHea-heaPum.scaFacCoo)/heaPum.scaFacHea < heaPum.limWarSca

Changing the control would be difficult, as

• the heat pump already runs at minimal part load, decreasing it further is not realistic
• Decreasing the minimal radiator temperature would lead to condensation effects in reality.
• Setting a minimal run time would lead to temperature violating the minimal radiator temperature.

So, this system would be a bad fit in reality, as well, as no energy storage decouple the low-inertia radiator from the oversized heat pump.

With the correct sizing, the behavior looks like this:

I wanted to trigger the warning to have examples for the different warnings which may occur.
I could change it to undersizing, so that the warning still occurs. Would that be fine for you?

In any case, I will update the doc of the example to explain to conflict of sizing for these systems.